Carburetor



June 14, 1932. p w, ENSlGN 1,863,195

/ CARBURETOR Filed July 15, 1950 5 Sheets-Sheet l l'nve for. Paul. Z11. Ensgyw.

June 14, 1932. P. w. ENSIGN CARBURETOR Filed July 15, 1930 5 Sheets-Sheet 2 I nvep for Paul. Z0. Z'zzszyrv.

June 14, 1932.

P. w. ENSIGN CARBURETOR Filed July 15, 1930 3 Sheets-Sheet 3 can . MaoI MmQ .6 mqzbol omw 3 N685 E m 362w 9U RWQQ Qw b 95 aw 4 262% HES Ch klk R/iT/O. PUHNUJ 141R PER HOUR PflU/VDS F'uEL PER HOUR.

' Patented June 114 1932 PAUL w. Ensren, or sen iuanrno, canrronivrn, assreuon T ENSIGN ennnunnron co. run, or nunrmeron PARK, carrronma, a CORPORATION or cnnrrennrra CARBUEETGR This invention has reference to carburetors, and in certain of its aspects, deals with subject matter similar in part to the type of carburetor disclosed in my Patent No. 1,7l8,472 granted February 25, 1930, on carburetor, and the type of carburetor described in Patent No. 1,799,585, granted Apr. 7, 1931 to Orville H. Ensign on carburetor.

The objects of the present invention are directed most particularly to the provision in carburetors of the general'type disclosed in the above applications, of fuel metering means whereby comparatively rich fuel mixtures may be supplied. the engine at low speed operations under throttle control, and also under conditions of lugging operation; that is with the throttle substantially wide'open and the engine speed governed by the load. And it may be mentioned that it is primarily so for supplying the desired rich mixtures for low speed engine operation and acceleration under conditions of lugging operation, that the invention has its chief advantages.

in my copending application above referred to, proper and economical metering of fuel during operation under throttle control, is brought about by the provision, in combination with an improved arrangement of an idling by-pass accelerating well, and main fuel passage, of an economizer system of the type described in said application filed by. G.

H. Ensign. Rich mixtures are supplied the which delivers fuel at closed and slightly open throttle positions. For open or substantially open throttle positions however,

the idling by-pass is substantially inefi'ecthe same. during low speed lugging operation the mixture supplied the engine will be comparatively leaner since the idling fuel delivery. instead of being'under throttle control, is metered in accordance with the amount of air passing through the carburetor and which under: the conditions is insuilicient to produce a fuel mixture of the desired richness.

abling the proper rich mixtures for conditions of lugging operation to be supplied the engine independently of the throttle control, and yet however, so as not to interfere with, but rather improve, the low speed operation of the carburetor under throttle control. The manner in which the above objects are accomplished, as well as the various details of the invention, will be described to best advantage without further preliminary discussion, in the following detailed description of a typical and preferred form of carburetor employing the improvements provided by the invention. Reference is bad throughout' the description to the accompanying drawings, in which:

Fig. 1 is a vertical section taken on line l1 of Fig. 2; and illustrating a preferred embodiment of my invention as practically constructed Fig. 2 is a horizontal section taken on broken line 22 of Fig. 1;

Fig. 3 is an enlarged fragmentary vertical section taken on line 33 of Fi and idling by-pass arrangement with relaengine for lowspeed operation under throttle control by the action of the idling by-pass,

tual and therefore, other conditions being In accordance with the invention lihave tion to the main fuel passage;

Fig. 4 is afragmentary enlarged section on line 4-4 of Fig. 2 showing the fuel riser passage and compensating well;

Fig. 5 is a partially diagrammatic illustration of the carburetor, a number of themrious passages being shown in a single plane in order to facilitate description; and

Fig. 6 illustrates the fuel and air mixture curves for the carburetor for engine opera- 2, and showing particularly the accelerating well tion under lugging conditions and underthrottle control. I 1

For the purpose of showing a practical form ofmy invention, it shall first describe the structure and arrangement of parts shown in Figs. 1 to l which represent an actual carburetor construction. However, in those parts of the description concerned with the invention, reference will be had to best advantage to the diagrammatic view in Fig. 5, which'is better suited for this purpose. In Figs. 1 to 4, I have not attempted to show certain parts of the carbureter in fullest detail since the present invention is not concerned with such details. These however are more particularly shown and described in my co pending application Ser. No. 100,489. Figs. 1 to 4 have been included in the present application primarily for the purpose of showing a practical embodiment of the parts more diagrammatically illustrated in Fig. 5, through insuflicient detail or will enable those familiar with the art to have a clear understanding of at least one practical form of the invention. e

In the drawings, numeral 10 indicates the main air intake, in which is the usual choke valve 11. Air is drawn from intake through an upturning elbow 12 into the main suction passage13within which is placed a Venturi tube 14, and the control throttle 15 mounted immediately above the venturi in the usual manner. Suction passage 13 communicates atits. upper end, and above the throttle, with the engine intake manifold, this upper end portion of the passage being termed the outlet 13a. The carburetor is provided with the usual constant level fuel chamber 16, the flow of fuel from intake 17 into the chamber being controlled by suitable float controlled valve means as indicated at 18. No further mention need be made of the partsdescribed thus far since they are well known, and the particulanpurposes which they serve will be readily understood.

The present form of carburetor which I show for thepurposeof describing my invention, comprises in addition to the elbow 12, three main portions or castings, the first, generally denoted by 20 comprising the air inlet and suction passage, and also the idling by-pass, accelerating well, @te; the sec ond, indicated at 21 comprising mainly the fuel chamber 16 and associated parts; and a third, comprising a block 22, including primarily the parts and passages for. controlling the initial metering of fuel from thesu ply reservoir to the main fuel passage. arts 20 and 21 are jointed together in a vertical plane by means of screws 24, see Fig. 2, block 22 being clamped between castings 20 and 21 and secured to the latter by means of cap comprising an annular passage 27 surrounding the upper end 0f elbow 12, and which communicates with a vertical bore 28 open ing at its upper end through a horizontal bore 29, into the fuel reservoir above the liquid level therein. The elbow 12 is joined to the body of the carburetor by screws 12a. And it may be mentioned that the inlet elbow may be adjusted by turning relative to the main suction passage without throwing the balance passage out of communication with the inlet, since the circular passage or groove 27 in the elbow will remain in communication with passage 28 for all positions of the elbow. By thus establishing communication between the air inlet and the fuel reservoir, the air pressure on the fuel therein is caused to fluctuate with the pressure in the intake.

'Further details relating to the operation of such balance passages will require no further discussion in the present application, since the balance passage is fully described in Letters Patent'No. 1,506,220, onfcarburetors, issued Aug. 26, 1924, to O. H. Ensign.

The balance passage also communicates with the main suction passage through a restricted economizer port 28a located at a point somewhat below the edge of the throttle valve 15'whe11 the latter is in closed position. Those elements of the carburetor which go to make up the economizer, comprise the subject matter of said Patent 1,799,585 by O. H. Ensigna A brief description of the operation of the 'economizer, and a discussion of its cooperation with the compensator feed well which comprises a part of the present invention, will be entered into to best advantage at later points. i

Fuel is taken from the reservoir intoa vertical riser passage or bore 30 in block 22, which passage comprises a portion of the main fuel passage, by way of a valve controlled orifice 31 in the end of plug 32 screwed into a bore within the bottom of the clock. The flow through orifice 31 is controlled by means of needle valve 33; whidh is urged upward into engagement with cap34 by means of spring 35 confined between the upper face of the block and flange 36 on the upper'end of the valve. The fuel admitted to riser passage 30 througlrthe valve controlled orifice flows upwardly and over the lower edge of an unrestricted opening 37 into passage 38,

the fuel thence passing downwardly to the horizontal passage 39. A restricted flow of air is also taken into passage 30 through calibrated bushing 40 at its upper end, the fuel and air being mixed in flowing through opening 37 and the mixture conducted downwardly topass 'age 39. In the present form of carburetor, riser passage 30, bore 38 and passage 39 may be considered as comprising the main fuel passage. The size of the bore of bushing 40 is accurately calibrated in order to adapt the carburetor to'diflerent motors, and to supply a suitable amount of initial, air for admixture with the fuel with in limits permitted by the'other co-acting parts of the carburetor. Passage 30 communicates with the venturi at a point at or near its most restricted area, through fuel nozzle 42 threaded into a radial bore in the Venturi wall.

Further details of the construction and operation of the above. mentioned passages within block 22, and certain additional parts associated therewith, will be discussed to best advantage at a later point; The description of these parts .given so far, however, will permit a full understanding of the operation of the carburetor following the initial metering and delivery of fuel and air to passage 39, after a description of which I shall return to a more detailed description of the initial fuel metering operation and its relation to the other ports.

A vertical bore 43, closed at its lower end,

opens upwardly into passage 39 at an inter-* mediate point therein, bore 43 providing essentiallya sump into which a certain amount of fuel, or certain percentage of the fuel delivered to passage39, depending upon opcrating conditions, is permitted to flow. Bore 43 provides an intermediate low point or part in the horizontal passage39, and as will be seen, it is from this low point that fuel is taken off into the accelerating well means hereinafter described.

At a suitable point in fuel passage 39 between sump 43 and nozzle 42, is located a transverse port 44 communicating with the vertical idling passage bore 45 which leads at its upper end through diagonal bore 45a, into suction passage outlet 13a above the throttle. Lathe upper end of idling by-pass bore 45a is a bushing 47 having a calibrated restricted bore. Thus communication is had by way of the idling by-pass, between outlet 13a and fuel passage 39, at a point beyond, in the direction of fuel fiow, the point (sump 43) of fuel takeoff for the accelerating well.

An accelerating well means,communicates through port 48 with sump 43 at a point below passage 39, and comprises a vertical bore or passage 49 opening at its upper end through restricted orifice 5% into chamber 55. The latter communicates, by way of passage-52, with the outlet 13aabove the throttle, by way of calibrated bushing 53.

The accelerating well is provided at its uppee end with suction filling means and means to ,limit the height to which the fuel is raised. Air is controllably admitted to chamber from-above the liquid in thefuel reservoir, by way of a restricted port in calibrated bushing 56. Chamber .35 communi cates with passage 52 through the restricted port in bushing 5' As will later; be seen, bleeder port 56 forms the fuel limit 1ing means for the accelerating well, while suction port 57, etc. forms the suction filling means for the well. 1

Both ports 56, and 57 are formed in sepa-' rate screw threaded bushings. and their sizes are accurately calibrated to proportionately suit the other parts of the device and to obtain the proper interactions. .-A.s typical "examples of port sizes that have been found practically successful, I may state that ports 56 and 57 may be drilled .089 inch and'.035 inch, respectively, in diameter; and port 54: about .046 inch in diameter. Both ports 47 and 53 may be about .086 and port 1-4, about .070 inch in diameter. The exact sizes of the various bleeder ports will of course vary in applying the carburetor to different motors.

I shall now describe briefly the operation of the parts of the carburetor described up to this point under various conditions of engine speed and load, and for this purpose will refer particularly to Fig. 5. Under normal operation with throttle valve 15 somewhat open, the engine running at uniform speed, the flow of air through venturi 14. causes a suction to be exerted on fuel nozzle 42. As a result of this suction, fuel is drawn upthrough riser passage 30 to the point of overflow through opening 37, and such fuel, mixed with air drawn in through bleeder port 40, is taken into fuel passage 39. The mixed fuel and air are then drawn through nozzle 42 into Venturi tube 1% where the fuel and air mixture is combined with air flowing upwardly through the venturi.

Assuming the engine to be idling with throttle 15 substantially in closed position, the main air flow through the venturi is very small and a much higher suction is, by reason of the throttle closure, put upon port 47 than is put upon nozzle 42. The relatively increased suction on the idling by-pass causes fuel and air to be drawn through the fuel passage and from it through port as into passage 45 through which the fuel is delivered to the outlet. This suction at port 44 is also sufiicient to cause air to flow from the interior of the venturi through nozzle 42 to port 44, and thus-to mix with the fuel passing through this port. At, the same time a considerable flow of air will occur through bleeder port 40 and mix with the fuel being delivered to passage 38 through opening 37. The idling mixture may be adjusted to proper portion by regulating the depression applied to port There is provided for this purpose, a passage 60 which bleeds air from the lower entrance portion of the Venturi tube past the controlling valve 61, and through passage 62 into bore 45, which as before stated, comprises a portion of the idling by-pass. Thus during idling operation there is mixed air and fuel flowing to the idling the engine is idling, .to cause enough depression in passage 30 to lift fuel over the lower edge of opening'37. J In the particular design shown, the depression necessary to lift fuel 'from level L in the fuel reservoir over the overflow edge of opening 37 iscomparatively small since the vertical distance is small. The depression at port 47, withythe throttle closed,

' is many times greater than that necessary to lift the fuel through opening 37 and the fuel and air mixture from port 44 through port 47. Therefore port 44 will be small as compared with the combined openings of nozzle 42 and bleeder port 40.

For closed or slightly open positions of the throttle, the suction exerted upon the accelerating well through ports 53, 57 and 54, is sufiicient to draw fuel up from fuel passage 39, or more properly -sump 43, through restricted port 54 and into chamber 55 to the level-of port 57. During filling of the accelerating well. some air will be drawn up into the well along the fuel. Upon a very small amount of fuel attempting to pass :5. through port 57. the fuel in effect, chokes the port, and the suction through 57 is so checked that the air taken in through port 56 will satisfy the suction suflicientlyto check further rise of the fuel. Anysmall amount of an fuel which may pass through port 57 serves as partof the idling fuel, the major portion of which is flowing through the idling bypass. Thus the rate and amount of fuel rise in the accelerating well is governed mainly by :5 the depression acting upon that well through port 54. that depression acting against grav ity and against the depression in fuel passage 39. Since the depression in passage 39 is governed by'adjustment of valve 61, the adjustment of the valve also has an interaction on the accelerating well. This however need not be gone into in detail in the present application. With the throttle closed or nearly closed. at any engine speed, the depression applied through port 53 is sufficient to cause the fuel to rise quickly to the top ofthe ac celerating well. For intermediate positions of the fuel level in the well. it may be stated that the height to which the fuel will be drawn up will depend on engine speed and throttle position. I

As the depression on the well is decreased due to the throttle being opened to intermediate positions, the fuel level in the well immediately falls. In falling away of the fuel level from port 54, port 57 is freed of the dog.

ging fuel and the effective depression on the well tending to draw the fuel upward therein is relatively increased, or in other words, the depression is maintained on the well without a sudden drop at initial lowering of the fuel I level. A small opening of the throttle does not causethe well to empty, the fuel instead I remaining ata lower level and without surging as long as the engine speed and position of the throttle remain the same. The fuel dropped out of the well as a result of partial lowering of the fuel lever, is returned to fuel passage 39 to supply extra fuel required for acceleration, the fuel remaining in the well being available for further acceleration.

Although the amount of fuel dropped from the well depends on both engine load and the amount and quickness of throttle opening, usually a quick wide-opening of the throttle will immediately empty the well and cause the carburetor then to operate normally.

As'previously mentioned the space above the liquid in the fuel reservoir communicates with inlet 10 by way of balance passage 28, and with suction passage 13, through restricted port28a opening into said passage. Port 28a is located below and near the lower edge of the throttle at the-closed throttle position, so that when the throttle is opened to a small fractional load position, depression is applied from above the throttle to the balancing system, thereby affecting the pressure in the fuel reservoir.

When thethrottle valve 15 is closed or at idling position, substantially no depression is applied to the float chamber by way of port 2 8a and passage 28,,or through the accelerating well filling passage. As the edge of the throttle approaches port 281; as the eng-ine takes on load however, the high depression above the throttle is applied to the bal- 1 a,nce passage causing an increased depression in the float chamber. The effect thus had by diminishing the pressure on the fuel in the float chamber is to reduce the delivery of fuel to the main fuel passage at the proper. point at which the engine can operate on leaner mixture, and ,thereby provide for highly economical performance. When the throttle is wide open, no appreciable effect will be had on-the pressure in the fuel chamber due to the application of suction through port 28a since the latter is so small in proportion to passage 28 that any effect had on the mixture will be inconsiderate.

In a carburetor applied to an automobile 'engine, the location of port 28a should be such that the throttle upon opening will pass will begin however late enough in the open ing movement of the valve that the idling action will not be interferred with. the described economizing action is under control of the throttle, the location of port.

28a may be determined so as to modify the mixture throughout that portion'of the power ,curve under throttle control, that the very thinnest mixture that can be satisfactorily Since burned in the engine cylinders will be delivered when the speed is under control of the throttle. i The parts described up to this point operate characteristically to take fuel from the supply chamber intothe main fuel passage over an inverted trap above the liquid level,

and to meter and deliver to the engine the fuel taken into the suction passage, in proper 19 and economical amounts and proportions for various conditions, or change in conditions,

- of engine load and speed, thereby bringing about smooth engine performance.

The main fuel passage has communication with the fuel chamber, independently of the valve controlled opening 31, at a point in riser passage 30below the liquid level therein, by way of what may be termed an auxiliary fuel passage. Referring particularly to 20 Figs. 4: and 5, the auxiliary fuel passage comprises a compensator well 65 communicating at its lower end with passage 30 by way of restricted port 66, and with the fuel chamber at a substantial distance below fuel level L,

through restricted port 67. Air is taken into the compensator well from the space above the liquid level in the fuel chamber, through the restricted opening in calibrated bushing 68 in. the. upper end of the well. A small 39 bleeder opening 69 is drilled through the wall between passage and well 65, preferably a short distance below the normal fuel level L. i

As a practical illustration of the sizes of the various ports in a carburetor of about the size shown in Fig. 5, I may state that air bleed ports 40 and 68 may be about .063 and .073 inch in diameter, respectively, ports 66 and 67 each .052 inch in diameter, and ports 69 40 and valve control opening 31 in neighborhood of .040 and .082 inchin diameter, respective ly. Ports 66 and 67 thus will be substantially the same size, and under any condition the size of port 66 will be less than the combined areas of ports 67 and 68, the reasons for which will presently appear.

7 As previously stated, the invention is concerned primarily with improvements whereby the engine may be supplied with compara- C tively richmixtures for low speed operation or acceleration from low speed under lugging conditions, that is with the throttle substantially wide open and with the speed controlled by engine load, and yet maintain the hereinabove described conditions of economical operation at higher speeds. This is accpmplished, generally speaking, by the provision of an auxiliary fuel supply system which is brought into operation to supply rich mixtures at such times as required for taking on load under lugging operation, or for low speed operation when the speed is under either throttle or load control. I And aswill beseen, the said auxiliary feedsupply system has such characteristics of operation in through port 66.

combination with the economizer parts, as to enable the latter to operate to supply leaner and most economical mixtures at such times as rich mixtures are not needed as the engine takes on speed or load.

For idling speed operation under throttle control, or for low speed lugging operation under heavy load and with the throttle substantially wide open, the depression in fuel passage 39 is comparatively little, although sufficient to raise the fuel in riser passage 30 to the point of overflowing opening 37. Under such conditions it is desirable that the fuel have ready delivery from the supply source to passage 39, and that the delivery of fuel thereto be unrestricted to the extent that is will be responsive to the slightest depression, or change of depression, in the fuel passage. Such action is accomplished by the compensator well, as will now be seen. At idling speed, and when the suction in 39 is comparatively small, the rise of fuel in passage 30 to the height of opening 37 will be accompanied by a simultaneous flow from the compensator well through port 66 into the passage. With the engine operating at slow or idlingspeed, the fuel level in the compensator well will not lower to any great extent since the flow into the well through port 67 will substantially take care of the dis charge through 66. Ready discharge of fuel from the compensator well is brought about under such conditions due to the fact that bleeder port 68 does not for extreme low speed operation retard the discharge of fuel from the well, as at higher speeds as will be presently described, and therefore the fuel is allowed to discharge freely from the well under ahead corresponding to the height of fuel therein.

Prior to the fall of the fuel in the well from its normal level to below ports 69, a certain amount of discharge into the riser passage may occur through that port, though in comparatively smaller amounts than that taken As the engine speed increases, the fuel level in well may drop to level L, whereupon port 69 will be uncovered and a certain amount of air bleed will occur through ports 68 and 69 into the riser passage. The effect had will be to decrease somewhat the suction in passage 30 and therefore retard, or prolong in proportion to the amount of air flowing through the main suction passage, the dumping of fuel from the compensator well, all of which will be more readily understood at a later point from the description of the curves in Fig. 6. Port 69 may be located at any suitable point intermediate the normal fuel level and port 66 in accordance with the manner in which it is desired to control the dumping of the compensator well, and in some cases it may be found suitable to provide two or' more such ports at vertically spaced intervals. An additional action is had by the air bleed into the a and L.

riser passage through 69 in that such air tends to areate the column of fuel in passage 30 above port 69 and in so, doing facilitate raising of the fuel to the point of overflowing through opening 37.

For intermediate positions of the fuel level in the compensator well, fuel is caused to flow from the float chamber into the well through port 67 under a gravity head corresponding to the difierence in height between levels L The flow thence from the well into riser passage 30 through port 66 will occur under a head corresponding to the height of level L, the fuel head within the well of course being a measure of the suction applied to port 66, modified by bleeder 68.

Upon the increase of engine speed substantially above idling, the depression applied to port 66 may be suiiicient to cause all or substantially all of the fuel in the compensator well to be drawn into the riser passage. After well 65 has become emptied, the fuel flows directly from the reservoir through ports 67 and 66 into the riser passage, the'flow through 67 occurring under a head corresponding to the height of the normalfuel level L thereabove. And with the well empty, increasing suction applied to port 66 from the riser passage will of course cause increasing amounts of fuel and air to be taken in through ports 67 and 68 respectively.

The size of ports 66 and 69 with relation to bleeder 68 is such that as the'suct-ion in the fuel passage increases to a certain point, and usually at a point at which a substantial amount of the fuel has been taken from well 65, or when the fuel level therein has fallen below port 69, restriction of the air flow into the compensator well will be offered by bleeder port 68; and as the suction increases,

' I the restrictive effect of port 68 on the air taken into the well will become progressively greater. As a result of this action, the amount-of fuel taken from the compensator well into thefuel passage, relative to the suction applied to the latter, decreases as the suction increases, or'in other words, as the suction progressively increases as the engine speeds up beyond idling and during empty ing of the compensator well, the amount of fuel taken from the well,'relative to that taken in through the valve controlled. inlet 31, wil decrease. Due to such decrease, the

roper fuel mixture is delivered to the engine in that progressively leaner mixtures are I supplied as the engine increases. And it may be noted that the action of bleeder 68 in retarding the withdrawal of fuel from the compensator well by restricting the air flow theremto, will continue until the well becomes completely emptied. i

As previously mentioned, after the compensator well hasvbecome emptied, fuel and air are taken through pofts 67 and 68 directly to port 66 into the riser passage in accordan'ce with the depression the-rein. However, as the suction increases beyond the point at which the compensator well is initially emptied, the fuel mixture taken through port. '66 into the riser passage becomes progressively thinner due to the fact that as the suction increases a proportionately greater amount of air is taken in through bleeder 68 than of fuel through 67. This apparentlyis due to the les'ser'viscosity of the air which causes, under conditions of increasing sucpoint at which the compensator well has become emptied, and as required for efficient engine operation. 7

It will be understoodthat the relative portions of fuel taken from the compensator well and through inlet 31, and the point at which a relative decrease in the amount taken from the well initially occurs, will be determined by the proper regulation of the size of the bleeder 68 with relation to the area of ports 66 and 69." Having once determined the size of bleeder 40 for proper operation of the parts of the carburetor communicating with the fuel passage beyond opening 37, the desired effect and cooperation of the compensator well may be had merely by providing a bleeder 68 of the proper size.

Reviewing briefly the operation of the compensator well, durlng idling speed operation and prior to the lowering ,of the fuel in the well below port 69, a mixture of maximum richness wil be supplied the engine. :Upon

lowering of the fuel level below port 69, however, initial thinning of the mixture occurs due to the effect of the air bleed in reducing the proportionate suction applied to port 66. And thereafter, as the engine speed increases, further and progressive decrease in the richness of the mixture occurs as the restrictive effects of bleeder 68 'isbrought into, action. Atthe point at which the compensator well becomes completely emptied, the mixture being supplied the engine is comparatively lean and may approach the normal proportion and has emptied, by virtue of subsequent thinning of the mixture by the air taken into the {Ijwell through bleeder 68, as previously explained.

The effect hadby the action of the compensator well on the fuel mixture supplied the u engine at low speed operation will be underto be identical with the type described, and

the other to be similar except that ports 66 and 69 are plugged and suitable adjustments of valve 31 and bleeder are made to adapt the carburetor to perform most efficiently without the compensator well.

In Fig. 6, the mixture ratio, that is the proportion of pounds of air per hour to pounds of fuel per hour is plotted against the amount of air per hour passing through the carburetor. Dotted line curve Crepresen'ts the operation of the carburetor without the compensator well under lugging conditions,- that iswith the throttle wide open and at 4 varying engine speed under load control.

Curve C'represents the operation, under similar conditions, of the carburetor equipped with the compensator well Itwill be noted that beyond or to the right of certain point X at which the amount of air per hourtaken through the carburetor is roughly about onehalf the maximum at point B, the two curves C and C are substantially in conformity, thereby indicating that beyond point X the compensator well may have no appreciable effect on 'the mixture ratio. To the left of point X however curve C showsa compara tive increase in richness of the fuel mixture in the direction of decreasing amounts of' air, or decreasing engine speed. This curves C and C indicate comparatively that for ex tremely low speedoperation under lugging conditions the compensator well operates to provide a-maximum' enriching of the fuel mixture over that which would bc had without the compensator well, and the relative enricliening decreases up to the point X at which the mixture ratios become substantially the same. The operation of the carburetor may be such that at point X, substantially all the fuel may have become drawn from the compensator well, in which event the curve from S to X represents the interval during which the fuel is being t aken from the well;

or, the well may have become emptied before brought about by virtue of :the air bleed through 68. Due to the effect of bleeder 68 after the compensator wellhas emptied, curves C ordinarily will fall below C beyond point X. It may be mentioned that the slope.

regulating the size of bleeder 68 and the loca- I tion and size of port 69.

' Curves K and K similarly represent the comparative fuel mixture ratios with and without the compensator well, with the throttle position varying and the engine speed constant under load control. Thus as indicated by the compensator well curve K. a comparat'ively rich mixture is had at closed and slightly open throttle positions up to a point Y at which curves K and K substantially come to- 4 gether, the curve from Sto Y again representing the interval during which the compensator well is emptied. In this case however point Y lies somewhat to theright of point X, the reason for which is due to the action of the economizcr in applying a depression to the fuel in the float chamber, as previously explained, when the engine is op erating under throttle control. Thus the effect had by the economizer at slightly open throttle positions, is to reduce the effective suction on the compensator well from the main fuel passage, and thereby prolong the emptying of the well in time and in proportion to the amount of air taken through the carburetor. The combined operation of the compensator well and the economizer thus brings the desirable result of prolonging the emptying-of the compensator well from a standpoint of time, and also from a standpoint of throttling position and therefore the; quantity ofair taken by the engine.

Although the described action of the coinpensator well is desirable at low speed operation under throttle control, itis particularly effective in supplying the proper rich mixtures under conditions of lugging operation with the throttle wide openand at such times as the engine is required to take on load run- I ning at low speed. Thus as will be seen from curve C should the engine while running at a low speed corresponding to 'the point S he suddenly required to take on load and pick up speed under such load, the necessary rich mixture will be supplied until an operating speed! corresponding to the point X is attained, at which point proper engine operation will be had using the normal fuel mixture.

I claim 1. In a carburetor, a throttle controlled suction passage, a fuel supply source, a main fuel passage. communicating with said supply source and discharging to saidsuction passage, an auxiliary fuel passage communicating with said main fuel passage at a point between its communication with the supply source and with said suction passage, fuel being taken fromsaid auxiliary passage into the main fuel passage by virtue of the suction 1n the latter, said auxiliary passage also having communication with the supplyisource 5 independently of the main fuel passage, and

suction operated means governing the delivcry of fuel from said auxiliary passage to the main fuel passage and opposing the tending of suction in the main fuel passage to draw fuel from the auxiliary passage into said main fuel passage.

' 2. In a carburetor, a throttle controlled suc' tion passage, a fuel supply source, a main fuel passage communicating with said supply 5 source and discharging to" said suction passage, an auxiliary fuel passage comprising a a 0 main fuelpassage, and there being a restri'ct- 3. In a carburetor, a throttle controlled suc- I tion passage, :1 fuel supply source, a main fuel passage communicating with said supply source and discharging to said suction pas-.

sage, an auxiliary fuel passage communicating with said main fuelv passage atv a point between its communication with the supply source and with said suction passage, said auxiliary passage also having communication with the supply source independently ofthe ed orifice for supplying air to said auxiliary fuel passage. Y I

4. In a carburetor, a throttle controlled suction passage, :1 fuel supply chamber, a. main fuel pasage' communicating withsaid suction passage, a'well supplied with fuel from said i fuel supply chamber through a restricted orifice, a' restricted outlet through which fuel is taken from said well into said main fuel passage, there being an air bleed from said well into the main fuel'passage at a point below the normal fuel level in the well, and an air bleed for supplying air to said well.

5'. Ina carburetor, a throttlecontrolled suction passage, a fuel supply source,a main fuel passage communicating with said supply source and discharging into the said suction passage, an airbleed forsaid fuel passage independent of the suction passage, an auxiliary fuel passage comprising a compensator well communicating with said main fuel passage at a point between its communication with the supply source and said air bleed, said well also taking fuel from the supply source 65 independently of the main fuel passage, and

suction operated means governing the delivery of fuel from said compensator Well to the main fuel passage and opposing the tendency of suction in the main fuel passage to draw fuel from the auxiliary passage into said main fuel passage. V

6. In a carburetor, asuction passage having an inlet, and outlet, and a throttle between said inlet and outlet, a fuel supply chamber, a main fuel passage communicating with said chamber and said suction passage,

said fuel passage consisting of an inverted trap extending above the fuel level in the supply chamber and over which fuel is raised in metered quantity by suction applied from the suction passage, a compensator well having communication with said main fuel pasa sage and with said fuel chamber at a point below the fuel level therein, and an air bleed for said compensator .well taking air from a source independent ofthe fuel passage. 7

7. In a carburetor, a suction passage having an inlet, anoutlet, and a throttle between said/inlet and outlet, a fuel supply chamber, a main fuel passage communicating with said chamber and said suction passage, said fuel passage consisting of an inverted trap extending above the fuel level in the supply chamber and over which fuel is raised in metered quantity by suction applied from the suction passage, a compensator well having communication with said main fuel passage, and independent communication with ,said fuel chambenat at point below the fuel level therein, abalance passage communicating between said inlet and the space above the liquid level in the fuel chamber, and an air bleed for said compensator well taking air'from said space.

8. In a carburetor, asuction passage having a throttle therein and outlet beyond the throttle, a fuel supply reservoir, a main fuel passage'communicating with said reservoir and said suction passage, said fuel passage consisting of an inverted trap extending above inc the reservoir fuel level and over which fuel is raised in metered quantity by suction applied from the suction passage, a compensator well for supplying auxiliary fuel to said main fuel passage, said well having independent com munication with the fuel reservoir, a restricted port communicating between the well and said fuel passage at a point below the normal fuel level, fuel being taken from the com pensator well into the .fuel passage through said port,-a restricted bleeder port communi eating between said well and the fuel passage at a point above the firstmentioned port, and

an air bleed for said compensator well taking air from a source independent of said fuel passage.

9. In a carburetor, a suctionpassage having a throttle therein and an outlet beyondthe throttle, a fuel supply reservoir,'a main fuel passage communicating with said reservoir rescues including a riser passage extending above the reservoir fuel level and having an outlet at its upper end, suction being applied to said riser passage outlet from the suction passage, a compensator well for supplying auxiliary fuel to said riser passage, said well having in dependent communication with the fuel reservoir through a restricted orifice located a substantial distance beneath the fuel level therein, a restricted fuel feed port communicating between said riser passage and the compensator well, a bleeder port between the well and the riser passage located at a pointvertically intermediate said fuel feed port and said outlet, and restricted air bleeds for said well and said riser passage, located at points above the normal fuel level.

10. In a carburetor, a suction passage having a throttle therein and an outlet beyond the throttle, a fuel supply reservoir, a main fuel passage communicating with said reservoir and said suction passage, said fuel passage including ariser passage extending above the reservoir fuel level and having anoutlet at its upper end, suction being applied to the outlet from said suction passage, a compensator well for supplying auxiliary fuel to said riser passage, said well taking fuel from the fuel reservoir through a restricted orifice, a fuel supply port communicating between said riser passage and the compensator well, a bleeder orifice between the riser passage and compensator well and located above the last mentioned port, a restricted air bleed for said well taking air from the space in the fuel reservoir above the fuel level therein, and an air bleed for said riser passage also taking air from said space in the fuel reservoir.

11. In a carburetor, having a main suction assage provided with a throttle,'an outlet eyond the throttle, a fuelsupply chamber,

' a main fuel passage communicating with the fuel supply chamber and discharging into the main suction passage; the combination of -an auxiliary fuel passage communicating with said main'fuel passageand with the fuel supply chamber, and throttle controlled means for transmitting suction from said main suctionpassage to the fuel supply chamber above the fuel level therein.

12. In a carburetor, having. a main suction passage provided with a throttle, an outlet beyond the throttle, a fuel supply chamber,

. a main fuel passage communicating with the sage through said auxiliary passage and op-- posing thetendency of suction; in the main fuelpassage to draw fuel from the auxiliary into said main fuel passage, and throttle controlled means for transmitting suction from said main suction passage to the fuel supply chamber above the fuel level therein.

13. In a carburetor, having a main suction passage provided with a throttle, an outlet beyond the throttle, a fuel supply chamber, balancing means connecting the air intake with the fuel chamber, a main fuel passage communicating with the fuel supply chamber and discharging into the main suction passage,- the combination of an auxiliary fuel passage comprising a compensator well communicating through a restricted port with said main fuel passage and taking fuel from said fuel chamber independently of said main fuel passage, an air bleed for said compensator well through which air is taken from the fuel supply chamber above the liquid level therein, and throttle controlled means for transmitting suction from said main suction passage to the fuel supply chamber above the fuel level therein.

1i. In a carburetor, a throttle controlled suction passage, afuel supply reservoir, :1- i'nain fuel passage communicating with said reservoir and discharging into said suction passage. an auxiliary fuel passage comprising a compensator well communicating with the fuel passage and taking fuel from said supply reservoir independently of the main fuel passage, a restricted air bleed for said well communicating with the fuel reservoir above the liquid level therein, and a throttle controlled means for transmitting suction from said main suction passage to the fuel chamber, comprising a port. connnunicating with the fuel chamber above the fuel level and located in the wall of the suction passage near but wholly spaced from the closed throttle and at the intake side of that edge of the throttle which moves toward the intake upon opening.

15. In a carburetor, a throttle controlled suction passage, a fuel supply reservoir, a main fuel passage communicating with said reservoir and discharging into said suction passage, an air bleed for said main fuel passage taking air from the fuel chamber above the liquid level, an auxiliary fuel passage comprisinga compensator well communieating with the fuel passage and taking fuel from said supply reservoir independently of themain fuel passage, a restricted air bleed for said well communicating with the fuel reservoir abovethe liquid level therein, and a throttle controlled means for transmitting suction from said main suction passage to the fuel chamber, comprising a port communicating with the fuel chamber above the fuel level and located in the wall of the suction passage ,near but wholly spaced from the closed throttleand at the intake side of that edge of the throttle which moves toward the intake upon opening.

16. In a carburetor, a throttle controlled suction assage, a fuel supply chamber, a

4 main fue passage communicating with said suction passage and having an outlet to which the suction in said suction passage is 6 applied, a well supplied with fuel from saidfuel supply chamber through a restricted orifice, a restricted port, separate from said main fuel passage outlet,through which fuel is taken from said well into said main fuel 10 passage, said port leading into said main fuel passage at a point between its communication with the supply chamber and said outlet, and1 an air bleed for supplying air to said wel 16 17. In a carburetor, a throttle controlled suction passage, a fuel supply reservoir, a main fuel passage communicating with said reservoir and discharging into said suction passage, said main fuel passage having an 20 outlet to which the'suction in said suction passage is applied, an auxiliary fuel passage.

comprising a compensator well having an outlet port separate from the main fuel passage outlet, communicating with the main 26 fuel passage at a point between-its communication with the supply reservoirand said outlet, said compen sator well taking fuel from i said supply reservoir, and a restricted air bleed for said well communicating with the 80 fuel reservoir above theliquid level therein.

1 18. Ina carburetor, a throttlecontrolled suction passage, a fuel supply source, a main fuel passage communicating with said sup- .ply source and discharging to said suction passage, an auxiliary fuel passage communieating with said main fuel passage at point between its communication with the supply source and with said suction passage, fuel being taken from said auxiliary passage into 40 the main fuel passage by virtue of the suction in the latter, said auxiliary passage also 7 having communication" with the supply source and means governing the delivery of fuel from said auxlliarypassage to the main 46 fuel passage and opposing the tendency of gsuctio'n in the 'main fuel passage to draw fuel from the auxiliary passage intosaid main fuel passage. j r

In witness that I claim the foregoing I have hereunto subscribed my name this 27th day of June 1930. F 1

1 s 7 PAUL W; ENSIGN. 

